Effect of series resistance on the electrical characteristics and interface state energy distributions of Sn/p-Si (MS) Schottky diodes

In this study, electrical characteristics of the Sn/p-type Si (MS) Schottky diodes have been investigated by current–voltage (I–V) and capacitance–voltage (C–V) measurements at room temperature. The barrier height obtained from C–V measurement is higher than obtained from I–V measurement and this discrepancy can be explained by introducing a spatial distribution of barrier heights due to barrier height inhomogeneities, which are available at the nanostructure Sn/p-Si interface. A modified Norde’s function combined with conventional forward I–V method was used to extract the parameters including barrier height (Φb) and the series resistance (RS). The barrier height and series resistance obtained from Norde’s function was compared with those from Cheung functions. In addition, the interface-state density (NSS) as a function of energy distribution (ESS–EV) was extracted from the forward-bias I–V measurements by taking into account the bias dependence of the effective barrier height (Φb) and series resistance (RS) for the Schottky diodes. While the interface-state density (NSS) calculated without taking into account series resistance (RS) has increased exponentially with bias from 4.235 × 1012 cm−2eV−1 in (ESS – 0.62) eV to 2.371 × 1013 cm−2eV−1 in (ESS – 0.39) eV of p-Si, the NSS obtained taking into account the series resistance has increased exponentially with bias from of 4.235 × 1012 to 1.671 × 1013 cm−2eV−1 in the same interval. This behaviour is attributed to the passivation of the p-doped Si surface with the presence of thin interfacial insulator layer between the metal and semiconductor.